Apparatus for recovering oil from the solvent cleaning or scouring of raw wool or wool fabric



March 17, 1953 DERBY APPARATUS FOR RECOVERING OIL. FROM THE SOLVENT CLEANING OR SCOURING OF RAW WOOL OR WOOL FABRIC Filed A ril 22, 1952 5 Sheets-Sheet l March 17, 1953 APPARATUS FOR RECOVERING OIL FROM THE SOLVENT CLEANING OR SCOURING OF RAW WOOL OR WOOL FABRIC Filed April 22, 1952 5 Sheets-Sheet 2 E DERBY 2,631,971

APPARATUS FOR RECOVERING OIL FROM THE SOLVENT CLEANING OR SCOURING OF RAW WOOL OR WOOL FABRIC I Filed April 22, 1952 5 Sheets-Sheet 3 March 17, 1953 R E DE I 2,631,971

Patented Mar. 17, 1953 APPARATUS FOR RECOVERING OIL FROM THE SOLVENT CLEANING OR SCOURING OF RAW WOOL OR WOOL FABRIC Roland E. Derby, Lowell, Mass.

Application April 22, 1952, Serial No. 283,544

Claims.

The object of this invention is to provide an apparatus for effecting the recovery of usable oil from the liquid resulting from the solvent cleaning or scouring of raw wool or Wool fabric.

In the treatment of wool in the various operations in the textile art, as for example in the carding, spinning and weaving processes, it is common to apply oil as a lubricant particularly to create a satisfactory slip between the fibers. The wool fiber itself also contains a certain amount of oil, grease or lanolin. Any oil thus present for these or any other reasons in raw wool or wool fiber is extracted therefrom in any solvent cleaning or scouring process, and its recovery from the liquid resulting from any such process is of substantial commercial importance because in particular such oil when recovered may be re-used as a lubricant for wool or for other purposes.

The object of the present invention is to recover such an oil freed from dirt and any component of fat derivatives which would otherwise render the recovered oil thick, gummy and unsatisfactory.

The present invention provides a novel and efficient apparatus for thus recovering in a commercially pure state such oil.

The solvent cleaning operation with the apparatus of this invention is preformed as a continuous process, and by the use of any suitable solvent. The continuous solvent cleaning operation of wool has been successfully developed in accordance with the invention disclosed in Letters Patent No. 2,176,705 granted October 17, 1939, and the solvent there employed is p erably of the chlorinated hydrocarbon group because of the non-inflammable and non-toxic character of such a solvent, and this is the most satisfactory, efficient and safe method particularly when large quantities of fabric or wool are to be handled. But at the other extreme, the wool may be solvent cleaned or scoured, whether in the form of fiber or partiall or wholly manufactured, by the batch process and by the use of the common inflammable solvents such as naphtha, when the danger from fire can be avoided or risked.

The basic principle of the process carried out by the apparatus of this invention resides in mixing with the liquid resulting from the solvent cleaning process an alkaline agent compatible with the solvent in a tank. This effectspartial saponification of the fats contained in the liquid, and coagulatesthe dirt and fatty matters causing the formation of a' coagulant mass which floats to the top of the tank and carries with it the bulk of the dirt in the liquid. At the same time any heavier dirt which has been held in suspension in the liquid but which does not appear to contain fats, sinks to the bottom of the tank in the form of a sludge. The liquid thus freed from the coagulant mass which has floated to the top and from the sludge which has sunk to the bottom, and which now is chiefly composed of the solvent and the oil which it is desired to recover, is now decanted to a suitable still in which the solvent is distilled from the decanted liquid thus leaving the oil substantially free from dirt to be drawn off from the still while the solvent passes to a suitable condenser and is there recovered.

The nature and objects of the invention will appear more fully from the accompanying description and drawings and will be particularly pointed out in the claims.

The drawings illustrate largely in diagrammatic form a preferred form of apparatus embodying the invention and is particularly designed to be embodied in an apparatus such as is illustrated in the aforesaid Letters Patent No. 2,176,705.

In the Figs. 1 to 5 of the drawings- Fig. 1 is a front elevation of the apparatus partially broken away and somewhat diagrammatical;

Fig. 2 is a rear elevation of the tank;

Fig. 3 is a right hand elevation of the tank;

Fig. 4 is a front elevation, and Fig. 5 is an end elevation of an auxiliary still.

Referring to the aforesaid Letters Patent No. 2,176,705, the liquid resulting from a continuous drying operation continuously discharges from a chamber I l indicated in Fig. 1 through a suitable filter or strainer and thence through a pipe indicated at I2 and I3 respectively, and it is this liquid from which the oil is to be recovered.

In the construction illustrated in Fig. 1, a multi-section tank i located beneath the tank ll, so that the liquid may flow by gravity thereinto, and preferably between the still and condenser illustrated in the patent. The number of sections of the tank will depend upon the size and speed of operation of the apparatus. As

, illustrated the tank is of generally rectangular port 22 near the top and the intermediate sections such as [5, l6 and I7 connect in sequence with each other and with the last section 18 through ports 23 midway the top and bottom. Suitable baflle plates 24 are also provided to divert the liquid discharged from one tank into the next toward the bottom and a baflie 25 p vents direct discharge through the port 22.

Suitable means are provided for mixing the alkaline agent with the liquid in the tank. In the construction illustrated the alkaline agent in liquid form is carried in a reservoir 26 and discharged therefrom into the pipe [3 thence into the tank section M in a continuous flow under the control of the valve 21. A stirrer 28, see Figs. 2 and 3, driven by a motor or other suitable means acts to effect a thorough mixture of the liquid discharging from the tank II and the alkaline agent discharging from the reservoir 26.

In the preferred continuous dry cleaning process, one of the chlorinated hydrocarbon group of solvents and particularly trichlorethylene or perchlorethylene is employed as most satisfactory because of its non-inflammable and nontoxic characteristics and efficient action. The alkaline agent to be mixed with such a solvent is preferably an alkaline liquid substantially anhydrous, non-soluble in, and of lower specific gravity than such solvent and for that purpose triethanolamine has been found best to effect the required saponification. The determination of the alkaline agent compatible with the solvent employed will however depend upon well known factors. Any alkaline agent will cause some saponification and with some degree of efliciency. Even water solutions of solid alkaline agents such as borax and soda ash are theoretically usable, but they separate rapidly in the liquid resulting from the solvent cleaning process and thus reduce efficiency. Furthermore in the case of the chlorinated hydrocarbon solvents, the presence of the amount of water necessary to carry in solution the solid alkaline agents causes a small amount of hydrolysis of the solvent and also some solution of the solvent in water which is undesirable. The matter of cost is also largely determinative as between the value of the solvent lost on the one hand,

and the greater cost of an alkaline agent such as triethanolamine over borax or soda ash.

The result of mixing the alkaline agent with the liquid obtained from the solvent cleaning operation is to effect a partial saponification of the fats contained in the liquid and coagulate the dirt and fatty matter causing a coagulated mass to form and float to the top of the tank. Since the mixing is continuously going on in the first section l4, little if any coagulation takes place therein but rapidly occurs in the succeeding sections. It is believed that the floating of this coagulant mass to the top is assisted by the use of an alkaline agent which itself is of lighter specific gravity than the solvent and that separation is efiected more efficiently due to such lighter specific gravity. At the same time there is a slight separation of heavier dirt which has been held in suspension and which does not appear to contain fats, and this settles to the bottom of the tank sections in the form of sludge.

The liquid in the tank thus freed from the coagulant mass at the top and the sludge deposited at the bottom is decanted from the tank through the pipe 29 into the still 30. There is usually little coagulant in the last section poses, which may be drawn off through the drain When the operation is stopped, or whenever it may be desired, the entire liquid freed from the coagulant mass and sludge is decanted into the still for the recovery of the solvent and oil, and for this purpose there is provided a pipe 35 opening through valves 36 into the tank sections near the bottom above the sludge and these valves are opened until the floating coagulant mass is lowered to just above the valves.

From time to time as the coagulant mass at the top and the sludge at the bottom accumulate, it is necessary to draw these materials off from the tank and preferably to recover there from the solvent therein. For this purpose an auxiliary still 31, shown more in detail in Figs. 4 and 5, is located below the level of the tank and provided with a jacket 38 heated from the steam pipe 39. A pipe 4!] provided with sections 4! opens into the several tank sections where the coagulant mass is formed at points somewhat below the discharge port 22. Each of these sections is preferably provided with sight glasses 42 and valves 43 and thus, when through the sight glasses the undesirable accumulation of the coagulant mass has been reached, the valves are opened, and the coagulant mass drained 01f into the auxiliary still 31. Another pipe 44 connected to the still is also provided with sections opening to the bottom of the tank sections and each controlled by a valve 45 so that by opening these valves the sludge accumulated at the bottom may also be drained off into the auxiliary still 31. Then by operating the auxiliary still, the solvent contained in the coagulant mass and sludge is distilled off and passes through the pipe 46 into the condenser 23 where it is there recovered. The auxiliary still is provided at the front with a removable door 47 enabling the waste mass remaining after the solvent is distilled off to be removed. This usually is of no value and is thrown away.

This application is a division of application Serial Number 62,736, filed November 30-, 1948, now Patent 2,607,786, granted August 19, 1952, directed to the process for which the apparatus of this invention enables the said process efiiciently and rapidly to be carried out.

Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is:

1. An apparatus for recovering oil and solvent from the liquid resulting from a, continuous solvent treatment of raw wool or wool fabric comprising a series of tank sections, the first section having a discharge port near the top connecting with the second section, the last section having a discharge port near the top, any section intermediate the first and last sections and the last section connecting in sequence through ports midway the top and bottom, means for continuously feeding to the first section and mixing therein the said liquid and a suitable alkaline agent acting to effect partial saponification of the fats contained in the liquid and coagulate the dirt and fatty matter, causing the coagulant mass thus formed to float to the top, a still, a pipe connecting the still and the discharge port of the last section for continuously decanting into the still the coagulant freed liquid, means for drawing off' from the still the oil freed from dirt and solvent, and valve-controlled pipe connections to any said intermediate section for periodically drawing off the coagulant mass formed and floating at the top.

2. An apparatus for recovering oil and solvent as defined in claim 1, together with a second set of valve-controlled pipe connections from near the bottom of the tank sections to the still to enable the coagulant freed liquid to be drained off to the still.

3. An apparatus for recovering oil and solvent as defined in claim 1, together with a second set of valve-controlled pipe connections from near the bottom of the tank sections to the still to enable the coagulant freed liquid to be drained off to the still, and valve-controlled discharge ports at the bottom of the tank sections to enable sludge deposited on the bottom to be drained 01f.

4. An apparatus for recovering oil and solvent as defined in claim 1, together with a second set of valve-controlled pipe connection from near the bottom of the tank sections to the still to enable the coagulant freed liquid to be drained off to the still, a third set of valve-controlled pipe connections extending from the bottom of the tank sections to enable sludge deposited on the bottom to be drained oil, and an auxiliary still to which the first and third sets of pipe connections extend for distilling off the solvent from the coagulant mass and the sludge.

5. An apparatus for recovering oil and solvent as defined in claim 1, together with a stirrer mounted in the first tank section, and means for continuously operating the stirrer to maintain a thorough mixture.

ROLAND E. DERBY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 863,061 Griswold Aug. 13, 1907 2,104,991 Hollerer Jan. 11, 1938 2,453,472 Teter et a1 Nov. 9, 1948 

1. AN APPARATUS FOR RECOVERING OIL AND SOLVENT FROM THE LIQUID RESULTING FROM A CONTINUOUS SOLVENT TREATMENT OF RAW WOOL FABRIC COMPRISING A SERIES OF TANK SECTIONS, THE FIRST SECTION HAVING A DISCHARGE PORT NEAR THE TOP CONNECTING WITH THE SECOND SECTION, THE LAST SECTION HAVING A DISCHARGE PORT NEAR THE TOP, ANY SECTION INTERMEDIATE THE FIRST AND LAST SECTIONS AND THE LAST SECTION CONNECTING IN SEQUENCE THROUGH PORTS MIDWAY THE TOP AND BOTTOM, MEANS FOR CONTINUOUSLY FEEDING TO THE FIRST SECTION AND MIXING THEREIN THE SAID LIQUID AND A SUITABLE ALKALINE AGENT ACTING TO EFFECT PARTIAL SAPONIFICATION OF THE FATS CONTAINED IN THE LIQUID AND COAGULATE THE DIRT AND FATTY MATTER, CAUSING THE COAGULANT MASS THUS FORMED TO FLOAT TO THE TOP, A STILL, A PIPE CONNECTING THE STILL AND THE DISCHARGE PORT OF THE LAST SECTION FOR CONTINUOUSLY DECANTING PORT OF THE STILL THE COAGULANT FREED LIQUID, MEANS FOR DRAWING OFF FROM THE STILL THE OIL FREED FROM DIRT AND SOLVENT, AND VALVE-CONTROLLED PIPE CONNECTIONS TO ANY SAID INTERMEDIATE SECTION FOR PERIODICALLY DRAWING OFF THE COAGULANT MASS FORMED AND FLOATING AT THE TOP. 